• 전력전자학회논문지
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• 제21권4호
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• pp.364-372
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• 2016

In this paper, a voltage controller for the seamless transition of a grid-connected inverter for ESS is proposed. The single-phase inverter is operated as a current controller when the grid is connected and as a voltage controller in the stand-alone mode when the grid is disconnected. Generally, in the case of grid recovery, the overcurrent may flow into the system because of the mismatch phase between the inverter output and grid voltages. The proposed controller resolves the overcurrent problem through phase delay problems with initial value feed-forward control of the integrator when the grid voltage is restored. The effects of the control method are simulated through PSIM, and the usefulness of the control method is verified through experiments.

• 전기전자학회논문지
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• 제23권4호
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• pp.1182-1186
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• 2019

본 논문은 ADC 컨버터 내장 단상 직입구동 20W BLDC 모터 개발 및 출력 특성에 대한 연구결과를 논하였다. PWM 인버터 스위칭을 통해 회전자를 구동시키고, 모터의 역기전력을 홀센서 위상각 신호보다 전기적으로 30° 앞서도록 위치시켜 최적의 스위칭 타임을 확보하도록 제작하였다. 특성평가의 주요한 결과로서 인버터 효율 최대 92[%], 시스템 효율 53.34[%]를 보였으며, 모터 효율은 57.85[%] 보였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권11호
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• pp.547-552
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• 2005

This paper describes a pseudo-random carrier PW technique for the power converters. The proposed method generates a new pseudo-random carrier by randomly composing a carrier with fixed frequency and a carrier with opposition phase. To confirm the validity of the proposed method, a single-phase multi-level inverter was implemented and tested. The experimental results show that the output voltage and current harmonics spectra of an inverter have broadening effect of harmonics, as only simple composition of fixed frequency carries.

• 전력전자학회논문지
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• 제17권1호
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• pp.85-92
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• 2012

In this paper, a 300[W] class boost type single-phase inverter system which can compensate voltage sag on source side is designed and implemented. This system is a two-stage conversion system composed of a boost converter and a PWM inverter. If the voltage sag has appeared at the point of common coupling, the boost converter would be operated to compensate it. The boost converter and the inverter were constructed on single smart power module(SPM) to implement low cost system. The system is designed for that the THD of output voltage is below 5[%]. Finally, the validity of the design for the inverter system is verified by both simulations and experiments.

• 전력전자학회논문지
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• 제11권4호
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• pp.313-320
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• 2006

본 논문에서는 단상 NPC 멀티레벨 인버터의 출력단 고조파 저감을 위한 LC 트랩 필터의 설계 방법을 제시하였고, 출력전압 THD와 출력전류 고조파 FFT 분석을 수행하였다. 제시된 LC 트랩 필터는 일반적인 LCR 필터와 종속 접속된 구조를 가지며, 스위칭 주파수에 동조되었다. 인버터 시스템은 고전력 응용에 적합한 NPC 멀티레벨 인버터를 사용하였으며, 제어기는 DSP(TMS320C31)을 사용하여 구성하였다. 제안된 시스템의 효용성은 시뮬레이션과 실험 결과를 통하여 증명하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.774-777
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• 2005

In this paper, a constant frequency phase shifting PWM controlled voltage source full bridge-type series load resonant high-frequency inverter using the IGBT power modules is presented for innovative consumer electromagnetic induction heating applications such as a hot water producer, steamer and super heated steamer. The full bridge arm side link passive quasi-resonant capacitor snubbers in parallel with the each power semiconductor device and high frequency AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is discussed and evaluated on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency soft switching PWM inverter topology, what is called class DE type. including the variable-power variable-frequency(VPVF) regulation function can expand zero voltage soft switching commutation range even under low output power setting ranges, which is more suitable and acceptable for induction heated dual packs fluid heater developed newly for consumer power utilizations. Furthermore, even in the lower output power regulation mode of this high-frequency load resonant tank high frequency inverter circuit it is verified that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.

• 전력전자학회논문지
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• 제21권4호
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• pp.343-350
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• 2016

Generally, the average phase current is sampled at the midpoint of a PWM signal for the vector control of an AC motor. The three-phase current can also be reconstructed from a DC-link shunt resistor by sampling the shunt voltage during the active vectors of the SVPWM. However, the reconstructed current is different from the average current because of the deviation of the sampling point from the midpoint of the PWM signal. This paper proposes an algorithm to estimate the average current from the reconstructed current in a single-shunt inverter. The proposed method is derived from the phase current slopes based on switching states and corresponding switching time. In addition, the proposed method is generalized for all the six sectors of the space vector hexagon. The validity of the proposed algorithm is verified with simulations and experiments.

• 전기학회논문지P
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• 제62권3호
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• pp.145-150
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• 2013

A novel AC to DC PWM converters with unity input power factor are proposed to overcome the above shortcoming. The main function of these converters is to shape the input line current to force it exactly in phase with the input AC voltage. Therefore, the input power factor can be improved to near unity and the input current harmonics can be eliminated. In this paper, half-bridge converter with two active switches and two diodes are utilized for low-cost type UPS configuration. By having only two semiconductors in the current path at any time, losses can be reduced over the conventional boost topology. Also, this converter provides controllable dc-link voltage, high power factor, and low cost type converter by simple power circuits. Simulation results show that the proposed half-bridge converter/inverter control technique can be applied to single-phase low-cost type UPS systems successfully.

• Journal of Power Electronics
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• 제18권6호
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• pp.1720-1728
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• 2018

This paper proposes a novel soft starting algorithm by using PWM inverter technique to control an amplitude of the motor starting current at a single-phase induction motor (SPIM). Traditional SPIM starting methods such as a Split-Phase, Capacitor-Start, Permanent-Split Capacitor (PSC), Capacitor-Start Capacitor-Run (CSCR), basically cannot control the magnitude of starting current due to the fixed system structures. Therefore, in this paper, a soft starting algorithm based on a proportional resonant (PR) control with a variable and constant frequency is proposed to reduce the inrush current and starting up time. In addition, a transition algorithm for operation modes is devised to generate a constant voltage and constant frequency (CVCF). The validity and effectiveness of the proposed soft starting method and transition algorithm are verified through experimental results.

• 한국정보통신학회논문지
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• 제7권8호
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• pp.1751-1758
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• 2003

본 논문에서는 V55 마이크로프로세서로 제어되는 반브릿지 인버터를 사용하여 영구 콘덴서형 단상유도 전동기의 가변속 구동에 대해 연구하였다. Patel의 알고리즘을 이용한 SHE(Selected Harmonic Elimination) PWM 구동방식에 의한 V/F 제어로 출력전압의 고조파분을 제거할 수 있으며, 속도의 제어 범위가 넓어짐을 알 수 있었다. 제안한 방법을 시뮬레이션과 실험의 결과로 입증하였다.